Ramirez said that as a result of the changes, Fonden would be expected to receive nearly $3 billion less this year.
The redistribution of funds will also allow state oil company PDVSA to improve its cash flow and boost investments in the oil industry, Ramirez said.
Last year, the state oil company sold to the Central Bank $46 billion, Ramirez said. This year, he said, if oil prices keep to the range where they have been, the oil company should provide about $49 billion to the Central Bank.
Ramirez spoke in front of a photo of Chavez saluting, and showed journalists a document with the president's signature.
The oil minister was among several officials who visited the ailing president last week in Cuba, where he has been recovering since undergoing a Dec. 11 cancer surgery.
Vice President Nicolas Maduro had announced on Saturday that during their meeting, Chavez made decisions on certain economic matters and had signed various documents. They included the decisions announced by Ramirez on Monday.
PDVSA has accumulated growing debts in recent years while Chavez has enlisted the company for additional government tasks including food distribution and supporting social programs.
Last year, the company's debt reached $40 billion after rising from about $16 billion in 2007. Ramirez has insisted, despite criticisms by some market watchers, that the company has an appropriate level of debt. He said on Monday that during 2012 it paid debts of more than $15 billion.
Ramirez also denied one news account that some foreign companies have been holding off on their investments in oil projects in the country due to uncertainty about Chavez's health situation.
The oil minister said he plans to meet on Tuesday in Caracas with Igor Sechin, chief executive of the Russian oil company Rosneft, along with more than 30 other representatives of Russian businesses. He didn't offer details of what they plan to discuss.